A Phase I, Multicenter, Open-Label, Multi-Part, Dose-escalation Study of RAD1901 in Postmenopausal Women With Advanced Estrogen Receptor Positive and HER2-Negative Breast Cancer

Stemline Therapeutics

Status and phase: Completed; Phase 1

Conditions: Advanced ER+, HER2-Negative Breast Cancer

Treatments: Drug: Elacestrant

Study type: Interventional

Funder types: Other

Identifiers

NCT02338349

RAD1901-005

Details and patient eligibility

About

The purpose of this study is to evaluate the safety, tolerability and preliminary efficacy of elacestrant (RAD1901) in patients with advanced ER+, HER2-negative breast cancer.

Full description

The primary objective is to determine the maximum tolerated dose (MTD) and/or recommended Phase 2 dose (RP2D) of elacestrant in patients with advanced ER+HER2-negative breast cancer.

The secondary objectives of this study are:

• To assess the safety and tolerability of elacestrant
• To evaluate the pharmacokinetics (PK) of elacestrant
• To evaluate the preliminary anti-tumor effect of elacestrant

Enrollment: 57 patients

Sex: Female

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

Key Inclusion Criteria:

1. Patients must be post-menopausal women, as defined in the protocol
2. 18 years or older
3. Patients with histological or cytological proven diagnosis of adenocarcinoma of the breast with evidence of either locally advanced, inoperable and/or metastatic disease
4. Part A, B, C: Patients must have received no more than 2 prior chemotherapeutic regimens and at least 6 months of prior endocrine therapy
5. Part D: Patients may have received up to 1 previous line of chemotherapy and must have previously received 2 or more lines of endocrine therapy for advanced/metastatic breast cancer as a single agent or in combination. Patients must have received fulvestrant as one of the previous lines of endocrine therapy and have had documented progression while on, or within 1 month after the end of, fulvestrant therapy for advanced/metastatic breast cancer. Patients must have received prior treatment with a CDK4/6 inhibitor

Note: This list is not complete. Further inclusion criteria is provided in the protocol synopsis.

Key Exclusion Criteria:

1. Prior anticancer or investigational drug treatment within the following windows:

   1. Tamoxifen therapy less than 14 days before first dose of study treatment
   2. Part A, B and C: Fulvestrant therapy less than 90 days before first dose of study treatment. Part D: Fulvestrant therapy less than 42 days before first dose of study treatment
   3. Any other anti-cancer endocrine therapy less than 14 days before first dose of study treatment
   4. Any chemotherapy less than 28 days before first dose of study
   5. Any investigational drug therapy less than 28 days or 3 half-lives (whichever is longer) prior to first dose of study treatment

2. Patients with untreated or symptomatic central nervous system (CNS) metastases

3. Patients with endometrial disorders, including evidence of endometrial hyperplasia, dysfunctional uterine bleeding or cysts

Note: This list is not complete. Further exclusion criteria is provided in the protocol synopsis.

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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57 participants in 1 patient group

Elacestrant

Experimental group

Description:

Part A, Dose Escalation: Patients will be assigned sequentially to escalating doses of elacestrant. Part B, Safety Expansion: Once the MTD has been identified and/or a RP2D has been selected, additional patients will be enrolled to further evaluate the safety, tolerability and preliminary efficacy of the RP2D. Part C, Tablet Introduction: A cohort of patients will be enrolled to evaluate the safety, tolerability, and PK of a tablet dosage form at 400 mg QD. Part D, Dose Expansion: A cohort of patients will be enrolled to evaluate the safety, tolerability, PK and preliminary anti-tumor effect of elacestrant in tablet dosage form at 400 mg QD PO in a group of patients with a more homogeneous prior treatment history

Treatment:

Drug: Elacestrant